Power circuit modules are commonly used in power conversion circuits. A power circuit module, which is typically a complete power circuit, can usually be used for conversion of DC/DC or AC/DC. The power circuit is generally provided therein with at least a power switching device that is also known as a switch in the art. Conversion of power supply is achieved by controlling the power switching device with a controller.
In general, power circuit modules with different power levels differ from each other in size and, thus in different packaging type. A power circuit module for a higher power application is typically larger in size. Accordingly, as being applied to a system board, the power circuit module of a relatively higher power is usually required to be provided with a heat radiator.
A power circuit module is usually applied to the system board in a certain packaging type. The power circuit module may typically include a substrate, a plastic housing for encapsulating the substrate, and a heat radiator for dissipating heat from the substrate. The packaging structure for different type of substrates should be different from each other slightly. A typical power circuit module without copper base plate is taken as an example for illustrating the packaging structure.
Power switching devices and corresponding circuits with control devices are placed on the substrate, and interconnections for the devices on the substrate are achieved by soldering and wire bonding. A packaging housing corresponding to the substrate includes a frame, a connection plate, a cushion pad and a pressure plate. The substrate is arranged in a sealed space formed by the connection plate and the frame. The connection plate includes a plate body, a bridge element and a gate signal terminal, and the bridge element and the gate signal terminal are located at the edging area of the plate body. When the connection plate is assembled together with the substrate and the frame, leading-out terminals are achieved by the bridge element and the gate signal terminal for connecting the power circuit on the substrate with an external system board. Heat generated by the power switching devices is dissipated through the heat radiator. The pressure plate, the cushion pad and the bridge element are required to achieve uniform pressure between the substrate and the heat radiator, for the further purpose of obtaining good contact between them. In an example, the cushion pad is sandwiched between the pressure plate and the bridge element. Pressure is evenly applied on the bridge element via the cushion pad, provided by the pressure plate fastened by screws onto the heat radiator, and then applied evenly on the substrate through pressure points of the bridge element, so as to enable the good contact between the substrate and the heat radiator. The thermal silicone grease is applied on the contact surface of the substrate and the heat radiator, such that a thermal resistance between the power module and the heat radiator can be reduced. Moreover, sealing materials are applied and cured between the substrate and the frame to forming the sealed space, with some encapsulation material filled in to protect the devices on the substrate, as the performances of the devices are easily be impacted by the external environment.
As can be seen from above, the typical power circuit module of higher power requires a relatively complex assembly due to its complicated structure, and it is difficult to reduce production cost.
The foregoing information is merely disclosed to facilitate understanding of background of the present disclosure. Therefore, the foregoing information may include information not constituting the prior art known to those of ordinary skill in the art.